Association of low potassium diet and folic acid deficiency in patients with CKD

Role of Peritoneal Equilibration Test in Assessing Folate Transport During Peritoneal Dialysis

OBJECTIVES

Low plasma folate levels have been reported in patients undergoing hemodialysis and peritoneal dialysis (PD) in clinical studies. However, folate transport has never been mentioned as a factor contributing to low plasma folate levels in patients undergoing PD. The peritoneal equilibrium test (PET) assesses the plasma creatinine level and glucose transport abilities. This study aimed to evaluate the association between plasma folate levels and folate transport during PD based on PET grades.

METHODS

This study recruited 50 patients who underwent PD for ≥3 months and were categorized according to PET grades. Data regarding plasma folate levels and dialysate folate were collected. The primary outcomes were the relationship between the PET grade and plasma folate level and between the PET grade and dialysate-to-plasma folate concentration ratio (D/P folate). Furthermore, the difference in the plasma folate level and D/P folate between men and women was assessed.

RESULTS

The plasma folate level and the D/P folate significantly differed among the 4 PET groups (both P < .001). PET grade was significantly negatively correlated with plasma folate levels (r = -0.56, P < .001) and positively correlated with D/P folate (r = 0.686, P < .001). In subgroup analysis, neither the plasma folate level nor the D/P folate significantly differed between men and women.

CONCLUSIONS

Our study provides clinical evidence that the PET grade is associated with the plasma folate level and D/P folate, regardless of sex. Larger cohort studies are warranted to assess the importance of folate supplementation during PD based on PET grades.

Folate Deficiency Enhanced Inflammation and Exacerbated Renal Fibrosis in High-Fat High-Fructose Diet-Fed Mice

The prevalence of obesity and chronic kidney disease (CKD) is increasing simultaneously and rapidly worldwide. Our previous study showed that folate deficiency increased lipid accumulation and leptin production of adipocytes. Whether folate plays a role in CKD, particularly obesity-related nephropathy remains unclear. To investigate the effects of folate deficiency on CKD in diet-induced obese mice, four groups of male C57BL/6 mice were fed either a normal-fat diet (NF) with folate (NF+f); NF without folate (NF-f); high-fat high-fructose diet (HFF) with folate (HFF+f); or HFF without folate (HFF-f) for 12 months during the study. The results showed that HFF increased not only body weight, fasting blood glucose, total cholesterol (TC), low-density lipoprotein (LDL)-cholesterol, and blood pressure, but also cytokines levels, such as interleukin (IL)-2, interferon (IFN)-γ, IL-17A/F, IL-6, monocyte chemoattractant protein (MCP)-1, and transforming growth factor (TGF)-β1. The indicators of kidney failure including urinary protein, neutrophil gelatinase-associated lipocalin (NGAL), renal type I and IV collagen deposits and leptin content, and serum creatinine were also increased by HFF. Folate-deficient diets further elevated serum TC, LDL-cholesterol, IL-6, tumor necrosis factor (TNF)-α, MCP-1, TGF-β1, and leptin, but decreased IL-10 level, and thus exacerbated renal fibrosis. To investigate the possible mechanisms of folate deficiency on renal injury, phosphorylation of pro-fibrosis signaling molecules, including signal transducer and activator of transcription (STAT)3 and small mothers against decapentaplegic (Smad)2/3, were assayed. Both HFF and folate deficiency significantly increased the phosphorylation of STAT3 and Smad2/3, suggesting synergistic effects of HFF-f on chronic renal inflammation and fibrosis. In conclusion, the results demonstrated that folate deficiency might aggravate inflammatory status and enhance renal fibrosis.

Understanding and Treatment Strategies of Hypertension and Hyperkalemia in Chronic Kidney Disease

Hypertension and potassium imbalance are commonly observed in chronic kidney disease (CKD) patients. The development of hypertension would be related to several mechanisms. Hypertension is related to body mass index, dietary salt intake, and volume overload and is treated with antihypertensives. In CKD patients, managing hypertension can provide important effects that can slow the progression of CKD or reduce complications associated with reduced glomerular filtration rate. The prevalence of hyperkalemia and hypokalemia in CKD patients was similar at 15-20% and 15-18%, respectively, but more attention needs to be paid to treating and preventing hyperkalemia, which is related to a higher mortality rate, than hypokalemia. Hyperkalemia is prevalent in CKD due to impaired potassium excretion. Serum potassium level is affected by renin-angiotensin-aldosterone system inhibitors and diuretics and dietary potassium intake and can be managed by potassium restriction dietary, optimized renin-angiotensin-aldosterone system inhibitor, sodium polystyrene sulfonate, patiromer, and hemodialysis. This review discussed strategies to mitigate and care for the risk of hypertension and hyperkalemia in CKD patients.

Mediterranean Diet Adherence and Nutritional Status in Dalmatian Diabetic Hypertensive Patients Regarding Presence of Chronic Kidney Disease—Is There Any Difference?

In recent years, the Mediterranean diet has emerged as one of the dietary patterns that could have positive effects on overall health as well in the treatment of non-communicable chronic diseases. The aim of this cross-sectional study was to determine differences in adherence to the Mediterranean diet (MeDi) and nutritional status in patients with type 2 diabetes mellitus (T2DM) and arterial hypertension (AH) regarding the presence of chronic kidney disease (CKD). Two hundred and forty-eight Dalmatian diabetic hypertensive patients (DDHP) were included, and 164 (66.1%) of them had CKD. Data about anthropometric parameters, clinical and laboratory parameters, as well as lifestyle questionnaire and Mediterranean Diet Serving Score (MDSS) were collected for each study participant. Furthermore, body composition was assessed using MC-780 Multi Frequency Segmental Body Mass Analyzer (Tanita). Body mass index (BMI) as well as waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR) were calculated. Results showed that only 8.9% of DDHP were adherent to the MeDi without significant differences regarding the presence of CKD. Therefore, only 9.1% of participants with CKD were adherent to the MeDi. Dietary recommendations were received by 52.8% of DDHP and 49.4% with CKD, while only 12.8% of those with CKD were adherent to the given recommendations. The results showed that 88.3% of DDHP and 87.8% of the DDHP with CKD were overweight or obese. Statically significant lower frequency of nut intake suggested by the MeDi was found in those participants with CKD (p = 0.02). Therefore, the significant associations between adherence to each MeDi component as well as MDSS score with the development of CKD among all study subjects were not found. In conclusion, the results showed a low level of nutritional care in our region and low adherence to MeDi among DDHP. According to the results, there is an urgent need to improve nutritional care in our region, with a special focus on the MeDi for this especially vulnerable population of patients.

Impact of Dietary Potassium Restrictions in CKD on Clinical Outcomes: Benefits of a Plant-Based Diet

In patients with advanced-stage chronic kidney disease (CKD), progressive kidney function decline leads to increased risk for hyperkalemia (serum potassium > 5.0 or >5.5 mEq/L). Medications such as renin-angiotensin-aldosterone system inhibitors pose an additional hyperkalemia risk, especially in patients with CKD. When hyperkalemia develops, clinicians often recommend a diet that is lower in potassium content. This review discusses the barriers to adherence to a low-potassium diet and the impact of dietary restrictions on adverse clinical outcomes. Accumulating evidence indicates that a diet that incorporates potassium-rich foods has multiple health benefits, which may also be attributable to the other vitamin, mineral, and fiber content of potassium-rich foods. These benefits include blood pressure reductions and reduced risks for cardiovascular disease and stroke. High-potassium foods may also prevent CKD progression and reduce mortality risk in patients with CKD. Adjunctive treatment with the newer potassium-binding agents, patiromer and sodium zirconium cyclosilicate, may allow for optimal renin-angiotensin-aldosterone system inhibitor therapy in patients with CKD and hyperkalemia, potentially making it possible for patients with CKD and hyperkalemia to liberalize their diet. This may allow them the health benefits of a high-potassium diet without the increased risk for hyperkalemia, although further studies are needed.

Nutritional neuropathies

Neuropathies associated with nutritional deficiencies are routinely encountered by the practicing neurologist. Although these neuropathies assume different patterns, most are length-dependent, sensory axonopathies. Cobalamin deficiency neuropathy is the exception, often presenting with a non-length-dependent sensory neuropathy. Patients with cobalamin and copper deficiency neuropathy characteristically have concomitant myelopathy, whereas vitamin E deficiency is uniquely associated with a spinocerebellar syndrome. In contrast to those nutrients for which deficiencies produce neuropathies, pyridoxine toxicity results in a non-length-dependent sensory neuronopathy. Deficiencies occur in the context of malnutrition, malabsorption, increased nutrient loss (such as with dialysis), autoimmune conditions such as pernicious anemia, and with certain drugs that inhibit nutrient absorption. When promptly identified, therapeutic nutrient supplementation may result in stabilization or improvement of these neuropathies.

Comparing the Effect of Folic Acid and Pentoxifylline on Delaying Dialysis Initiation in Patients with Advanced Chronic Kidney Disease

Background: We hypothesized that the nutrient loss and chronic inflammation status may stimulate progression in advanced chronic kidney disease. Therefore, we aimed to generate a study to state the influence of combined nutritional and anti-inflammatory interventions. Methods: The registry from the National Health Insurance Research Database in Taiwan was searched for 20–90 years individuals who had certified end-stage renal disease. From January 2005 through December 2010, the diagnosis code ICD-9 585 (chronic kidney disease, CKD) plus erythropoiesis-stimulating agent (ESA) use was defined as entering advanced chronic kidney disease. The ESA starting date was defined as the first index date, whereas the initiation day of maintenance dialysis was defined as the second index date. The duration between the index dates was analyzed in different medical treatments. Results: There were 10,954 patients analyzed. The combination therapy resulted in the longest duration (n = 2184, median 145 days, p < 0.001) before the dialysis initiation compared with folic acid (n = 5073, median 111 days), pentoxifylline (n = 1119, median 102 days, p = 0.654), and no drug group (control, n = 2578, median 89 days, p < 0.001). Lacking eGFR data and the retrospective nature are important limitations. Conclusions: In patients with advanced CKD on the ESA treatment, the combination of folic acid and pentoxifylline was associated with delayed initiation of hemodialysis.